Nuns who ran a hell hole children’s home in Northern Ireland were nearly psychotic, a former resident said.

The Sisters of Nazareth property in Derry was like Auschwitz, youngsters’ screams of despair still haunting survivors, the UK’s largest ever inquiry into institutional child abuse was told.

Inmates formed chain gangs to polish floors until they sparkled – with arms linked and rags under both feet – and were beaten with bamboo canes and straps.

One witness reported sexual abuse by older boys to a nun.

The sister allegedly said: “You are a bad boy, you are going to hell, nothing like that ever happened.”

He said the assault happened in St Joseph’s Home, Termonbacca.

The witness said: “That was the reaction, a coldness and heartlessness about the place that will always scare you.

“I never heard children cry like I have in that place, it was one of despair and that still haunts me a little bit, it was a scream of despair.”

The treatment of children in church-run residential homes is a key concern of the investigation being held in Banbridge, Co Down. It is chaired by retired judge Sir Anthony Hart and is considering cases in 13 residential institutions between 1922, the foundation of Northern Ireland, and 1995.

One witness described the atmosphere.

“It was a form of psychological abuse, you were rescued like a Jew, a tinker, a tramp born at the back of the road, you were worth nothing,” he said.

Another added: “The whole atmosphere of Termonbacca was not asking and not being informed, you were a number, you were not worthy of information, you were told what to do.”

He was transferred from Derry to Salthill, run by the Christian Brothers on the outskirts of Galway city.

“The comparison was two hell holes. Which was better? It is difficult to describe when things are bad, you are on a race to the bottom. Salthill was Auschwitz, Termonbacca was Treblinka, it was somewhat better.”

There were rare moments of kindness, a Christmas party at the nearby British Army base of Ballykelly, long before the polarising effect of the Troubles, a school master paying for a bus home when it was snowing and the boys were wearing short trousers.

“We often thought about ourselves as survivors. If you are trying to do something good in a sea of evil how do you survive and they were survivors too,” a witness said.

Bathing in Jeyes fluid, a detergent now used to clear drains, was common.

A witness said: “It was kind of like a Zyklon B gas chamber, it was the general cleaning method used for children.”

He alleged that aged five or six he was taken out of bed at night and sexually abused in a bathroom by a woman, perhaps a nun or a civilian worker.

“It was something that was happening outside my body... I am not there although I am there,” he said.

He added: “It is as clear today, sadly, because I would love it not to be so clear but the effects of it were monumental.”

He said nuns bordered on psychotic at times.

He added: “There was always a hovering threat of something about to happen, even if it did not happen, not happening was in itself a threat.

“It exploded in rage or very ironic, cynical, derogatory (comments) or anything that could be said that could purposefully put you into a psychologically negative landscape, that was their major modus operandi.”

He suggested the inquiry should recommend stringent legislation be put into place to prevent a repetition and called for religious orders to pay compensation.

“The damage has been done and is permanent and does not go away. They are on their own, they are lonely and sad and broken.”

Another witness suffered depression and was silent and withdrawn as a child, he is still seeing a doctor about mental health issues.

He was attacked by older boys, pushed onto the ground and beaten. “There were times I thought I was going to die – it was torture to face another day,” he said.

He later lived south of the border.

“The Republic of Ireland, I am sorry to say, was a cruel and unjust place for people of my background. There was no support,” he said.

“They did not want us at all, there was no understanding, there was a lot of ignorance.”

He said the Northern Ireland Executive should not delay because victims were ageing.

He added: “It is not how you deal with people at the top of society but how you deal with broken people like us.”

Another witness was forced to bring nuns canes to hit him with.

He said: “The only ones I knew were very, very cruel.”

He was once beaten for having a hole in his sock and also at school, for laughing when an ink pot exploded over a desk.

They would go to bed early, because being in bed was a form of control by nuns, he testified, adding he would be praying he did not wet the bed.

“They could get on with their praying, who they are praying to I am not too sure.”

Public hearings are due to finish in June 2015, with the inquiry team to report to Stormont’s power-sharing Executive by the start of 2016.